This invention is directed to the field of tension rollers on pulleys for rotatably supporting a belt with adjustable tension, and is more in particular directed to a pin or supporting member of the type disclosed in published U.K. Patent Application No. 2,102,531, wherein a conventional rolling bearing is mounted on a sleeve-shaped section or housing having a bottom or end wall having an eccentrically disposed bore. The entire tension roller may be swung about the shaft of the bolt extending through the bore for tightening the belt rotatably supported by means of the bearing, and the bolt may attach the tension roller to a housing. In a similar embodiment, disclosed in published U.K. Patent Application No. 2,103,332, the inner race of the rolling bearing is incorporated directly into the sleeve-shaped section. Tension rollers of this type are also disclosed in U.S. Pat. No. 4,457,740.
In both of these known embodiments the sleeve-shaped housing is made of one piece deep-drawn sheet metal, the bottom part having essentially the same thickness as the cylindrical walls and lying essentially in a radial plane. When the tension rollers are attached the bottom of the supporting member is heavily stressed by the head of the bolt. To prevent the bottom from bending under such stress in the known embodiments, they are designed to comprise a relatively thick wall. In one-piece designs such a supporting member requires the use of a metal sheet of overall greater thickness than that absolutely necessary for the cylindrical wall section which has a basically more stable geometric shape than the bottom part. In addition, the eccentric position of the attaching bolt likewise results in a non-coaxial stress of the bottom which increases the risk of misalignment of the entire tension roller. The high cost of such thicker material and the increased difficulty of manufacture with such material for producing sufficiently stable conditions provides reason for seeking a cheaper solution.
An object of the invention is to provide a supporting member of the type mentioned above which can use thinner sheet metal while still having satisfactory resistance to deformation of the bottom of the supporting member.